This invention relates generally to valve assemblies, and more particularly to valve assemblies including a first electrical actuator and a second electrical actuator.
Hydraulically actuated devices, such as fuel injectors, typically utilize internally mounted, movable valve members to control the flow of actuation fluid to one or more device components. For instance, a number of hydraulically actuated fuel injectors include a movable spool valve that acts as a flow control valve that controls the flow of actuation fluid to the top of an intensifier piston. However, when valves such as these are moved by hydraulic forces, there tends to be a lag time between exposure of the control hydraulic surface to the force and movement of the valve. Engineers have learned that a more abrupt start and end to injection events is preferable. Therefore, there is room for improvement in this field.
One solution that has proven successful is the use of a latching actuator valve to control fluid flow within the injector. One example of this type of valve is described in U.S. Pat. No. 3,743,898, entitled Latching Actuators, which issued to Sturman on Jul. 3, 1973. The latching actuator taught by Sturman includes a first solenoid coil and a second solenoid coil that are selectively actuated to move the valve member between a first, latched position adjacent the first coil and a second, latched position adjacent the second coil. While this solution appears satisfactory in some instances, there is still room for improvement. For instance, in an actuator such as this, the valve member is moved between its first and second positions by sending an magnetizing current to one of the solenoids while a demagnetizing current is sent to the other solenoid. Continued actuation of both coils, if not needed, can result in wasted power by the fuel injection system.
In addition, attempts have been made to improve upon this invention. For instance, U.S. Pat. No. 5,720,261, entitled Valve Controller Systems and Methods and Fuel Injection Systems Utilizing the Same, which issued to Sturman et al. on Feb. 24, 1998 illustrates one such purported improvement. In Sturman et al., a latching actuator is disclosed which also includes an armature movable between a first and second solenoid coil. The disclosed actuator includes two communication lines connecting each coil to the positive and negative terminals of the electronic control module. In other words, a total of four wires are needed for this actuator. However, engineers have also learned that a reduction in the number of fuel injection system components, especially electrical components, can lead to a more robust system.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention, an actuator includes a body. A first solenoid coil and a second solenoid coil are attached to the body. An armature is movable between a first position adjacent the first solenoid coil and a second position adjacent the second solenoid coil. An electrical circuit is electrically connected to the first solenoid coil and the second solenoid coil. The electrical circuit includes at least one current restrictor that is positioned and arranged such that current flowing in a first direction energizes only one of the first solenoid coil and the second solenoid coil and current flowing in a second direction energizes only an other of the first solenoid coil and the second solenoid coil.
In another aspect of the present invention, a valve includes a valve body. A first solenoid coil and a second solenoid coil are attached to the valve body. An armature is movable between the first solenoid coil and the second solenoid coil. A valve member is movably positioned in the valve body and is operably coupled to the armature. An electrical circuit is electrically connected to the first solenoid coil and the second solenoid coil. The electrical circuit includes at least one current restrictor that is positioned and arranged such that current flowing in a first direction can energize only one of the first solenoid coil and the second solenoid coil and current flowing in a second direction can energize only an other of the first solenoid coil and the second solenoid coil. The armature is moved to a first position adjacent the first solenoid coil when the first solenoid coil is energized. The armature is moved to a second position adjacent the second solenoid coil the said second solenoid coil is energized.
In yet another aspect of the present invention, a method of controlling fluid flow includes a step of providing a valve assembly that has a first solenoid coil, a second solenoid coil and a valve member that is operably coupled to an armature. The first solenoid coil and said second solenoid coil are electrically connected to an electrical circuit. The valve member is positioned in a first position, at least in part by energizing one of the first solenoid coil and the second solenoid coil and by limiting energization of an other of the first solenoid coil and the second solenoid coil. The valve member is moved to a second position, at least in part by energizing the other of the first solenoid coil and the second solenoid coil and by limiting energization of the one of the first solenoid coil and the second solenoid coil.